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Laurentian五大湖沉积物中210Pb和137Cs深度剖面的积累率、聚焦因子和年代趋势表
yaoxn@llas.ac.cn
2018-06-25
学科主题水体污染治理
来源网址http://portal.nstl.gov.cn/STMonitor/home/bianyi_recordshow.htm?id=64631&parentPageId=1530770106693&serverId=&controlType=openhome
内容摘要

Sediment cores from 41 sites were collected from the Laurentian Great Lakes during 2010–2014, sectioned into 0.5–2.0?cm intervals, and the activities of 210Pb, 137Cs, and 226Ra were measured in the upper 25 to 40?cm of the sediment column by gamma spectrometry. Sediment mass accumulation rates (dry mass) calculated from 210Pb profiles range from 0.006?±?0.001 to 0.59?±?0.06?g?cm−2?yr −1 and are similar to those reported in previous Great Lakes sediment studies. Sediment mass accumulation rates decreased with increasing water depth. 210Pb-based models in cores exhibiting favorable characteristics (i.e., those having the highest unsupported-210Pb activity at the sediment-water interface, exponential decrease of unsupported-210Pb with increasing depth in sediment cores, and a clear peak in 137Cs activity at some depth below the sediment-water interface) give calendar date profiles that are largely concordant with the maximum 137Cs peak activity at 1963. Sediment focusing factors derived from unsupported-210Pb inventories range from 0.09 to >5.34, and are well correlated with those derived from 137Cs inventories that range from 0.07 to 4.04, demonstrating the ubiquitous occurrence of horizontal sediment transport processes within the lakes. This more recent survey provides a Great Lakes-wide chronological framework for comparing the depositional histories and inventories of a wide variety of persistent, bioaccumulative and toxic pollutants that have been measured in the same sediment cores. This information will be useful for resolving scientific and practical issues pertaining to the environmental quality and management of contaminated sediments in the Laurentian Great Lakes ecosystem.

 
来源大湖研究期刊
存缴方式webcrawl
内容类型科技动态
URI标识http://www.corc.org.cn/handle/1471x/1632152
专题科技动态
推荐引用方式
GB/T 7714
yaoxn@llas.ac.cn. Laurentian五大湖沉积物中210Pb和137Cs深度剖面的积累率、聚焦因子和年代趋势表. 2018.
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